1. Field of the Invention
The present invention relates to a backlight assembly and a liquid crystal display device having the backlight assembly. More particularly, the present invention relates to a backlight assembly having a thin thickness and achieving an improved image quality, and a liquid crystal display device having the backlight assembly.
2. Description of the Related Art
Generally, liquid crystal display (LCD) devices correspond to flat panel display devices that display an image using liquid crystal (LC) installed therein. The LCD device includes a liquid crystal display panel for displaying the image, and a backlight assembly disposed behind the liquid crystal display panel for providing a light to the liquid crystal display panel.
In general, the backlight assembly may determine a weight, a volume and a power consumption of the LCD device. Particularly, the LCD device applied to electronic apparatus such as a cellular phone or a notebook computer is in demand to have a thin thickness, a lightweight and low power consumption. Thus, the backlight assembly has been developed to meet above demands of the LCD device. For example, Korean Patent Laid-Open Publication No. 2003-80825 discloses the back light assembly.
FIG. 1 is a cross-sectional view illustrating a conventional backlight assembly.
Referring to FIG. 1, the conventional backlight assembly 50 includes a light source 10 for generating a light and a light guiding plate 20 for guiding the light in a predetermined direction.
The light source 10 has at least one light emitting diode (LED) so that the backlight assembly 50 has a lightweight and low power consumption.
The light guiding plate 20 includes a light incident face 21, a reflection face 22 and a light exiting face 23. The light generated from the light source 10 is irradiated into the light incident face 21. The reflection face 22 is extended from one end portion of the light incident face 21, and the light exiting face 23 is enlarged from another end portion opposing the light exiting face 23 of the light incident face 21. The light incident into the light incident face 21 is emitted through the light exiting face 23. Here, the light guiding plate 20 has a flat shape in which the light exiting face 23 is substantially parallel to the reflection face 22. In addition, a height h of the light incident face 21 is substantially identical to a distance d between the reflection face 22 and the light exiting face 23.
The backlight assembly 50 further includes a plurality of optical sheets 30 disposed over the light exiting face 23 to improve characteristics of the light emitted through the light exiting face 23. A reflection plate 40 is additionally disposed under the reflection face 22 to reflect a light leaked from the light guiding plate 20 toward the light guiding plate 20, thereby increasing an efficiency of the backlight assembly 50.
In the conventional backlight assembly 50, a size of the light source 10 may determine the height h of the light incident face 21 and the distance d between the reflection face 22 and the light exiting face 23. As the size of the light source 10 increases, the height h and the distance d also increase. Additionally, an increase of the size of the light source 10 augments an entire thickness t of the backlight assembly 50 including the optical sheets 30 and the reflection plate 40. On the other hand, when the size of the light source 10 is reduced, the entire thickness t of the backlight assembly 50 is also decreased.
However, the reduction of the entire thickness t of the backlight assembly 50 may be limited in accordance with the size reduction of the light source 10. In addition, since the backlight assembly 50 includes the optical sheets 30 and the reflection plate 40, the entire thickness t of the backlight assembly 50 may not be further reduced.